Ophthalmic Dx Therapeutics Flashcards
Ophthalmic Surgery Patient Prep
- Fine clippers/ no clip
- Soft gauze free swabs
- 1:50 dilution providine-iodine = no hibi (irritant
- Sterile saline
Patient Consdierations
- Comfort
- Behaviour
- Anaesthetics
- Medications
- Appearance
Ophthalmic Meds - Tissue and Route of Admin
Eyelids = systemic
Conjunctiva = topical/ systemic
Cornea = topical
Anterior uvea = systemic/ penetrating topical
Retina = systemic
Choroid = systemic
Optic nerve = systemic
Orbital tissues = systemic
3 Barriers to Ocular Drug Delivery
- Cornea = Lipid epithelium -> water stroma -> lipid endothelium = hydrophobic and hydrophilic best = chloramphenicol
- Blood-ocular barrier - prevents systemic drugs entering aqueous, vitreous
- Avascular tissues = cornea, lens
Mydriatics - Parasympholytics
Tropicamide 1% and atropine 1%
Paralyses smooth muscles in iris sphincter and ciliary body
Mydriatics - Parasympholytics 4 Considerations
- Reduced tear produciton = KCS
- Induced ocular hypertension and IOP (glaucoma)
- Bitter = salivation - don’t use regularly in cats
- Mydriasis = lens luxation
Mydriatics - Sympathominetics
Phenylephrine
- Localise Horner’s syndrome
- 0.2-1%
- Mydriasis in <20 mins = post-ganglionic lesions
Atropine
Use = Therapeutic for ciliary spasm/ uveitis
Action = mydriasis an cyloplegia
Onset = 40-90 mins
Duration = >24hrs
Tropicamide
Use = diagnostic for full fundic exam
Action = mydriasis and cycloplegia
Onset = 15-20mins
Duration = 2-3hrs
Phenylephrine
Use = Diagnostic to localise Horner’s syndrome
Action = Mydriasis if post-ganglionic
Onset = <20mins
Duration = 3-4hrs
Local Anaesthetic Examples
Tetracaine, Lidocaine, Proxymetacaine
Onset = 5mins
Duration = 1-2hrs
Local Anaesthetic Uses
3 points
Diagnostic ONLY
- Tonometry
- Explore conjunctiva
- Diagnostic sampling
Local Anaesthetic Considerations
4 points
- Reduced corneal sensation increased chance of trauma
- Reduced sensation = reduced reflex tearing
- Epitheliotoxic long term
- Systemic toxicity in small patients
Tear Substitutes Functions
Lube
Improve comfort
Indications of Tear Substitutes
- KCS/ dry eye
- Qualitative tear film disorders
- General anaesthesia
- Ocular discomfort
Tear Substitute Considerations
- pH close to tears
- Sufficient surface tension
- Correct osmolality/ osmolarity
- Adequate corneal adhesion
- Prolonged contact time
- Preservative = multidose bottle
Tear Stimulator Function and Indications
Function = increase tears
Indication
- KCS/dry eye
- Qualitative tear film disorders
Tear Stimulators - Ciclosporin
Optimmune
Calcineurin inhibitor = immunosuppressant and direct lacrostimulant
Topical
Licensed 0.2% BID
1-2% solutions
Expensive
Tear Stimulators - Tacrolimus
Protopic
Calcineurin inhibitor
Topic BID
Unlicensed
Tear Stimulators - Pilocarpine
Cholinergic agonist = only use w neurogenic
Oral BID
Unlicensed
Bacteriostatic Antimicrobials
Chloramphenicol = Strep, E.coli, Enterobacter, Proteus, Mycoplasma
Fusidic acid (Isathal) = Staph, Strep
Bactericidal Antimicrobials
Fluoroquinolones = ONLY MELTING ULCERS
- Ciprolfoxacin
- Ofloxacin
Aminoglycosides = Pseudomonas, E. coli, Enterobacter, Proteus
- Gentamycin
Cyclic Polypeptides - Pseudomonas, E. coli
- Polymixin
Antivirals
Herpetic keratocinjunctivitis - cats
Famcyclovir = systemic, expensive
L-lysine = meh
Corticosteroid Benefits
- Inhibit chemotaxis and neovasc
- Reduce protein and cells exudate
- Stabilise blood-aq-barrier and lysosomal membranes
